By grinding with e.g. an angle grinder or a drilling machine, most grinding wheels used are either a flat wheel or a ring wheel, where some force is to be applied in order to hold the grinding wheel stable onto a surface wanted to be ground.
If a flat grinding wheel is used, it is furthermore difficult to grind concave surfaces without leaving distinct grinding marks from the circumferential edge of the grinding wheel.
If a ring wheel is used, where abrasive material is only located from the periphery of the grinding wheel and a distance in on the grinding wheel, for grinding the entire surface there is to be used a number of sweeping movements with the grinding machine, which can be tiresome for the operator who is to hold against the rotating movement of the grinding machine simultaneously with the sweeping movements.
If grinding in recesses/countersinks, it is difficult to use the prior art grinding wheels as it is not possible to move the abrasive parts of the grinding wheel down into recesses/countersinks in a satisfactory way, so that an evenly ground surface is left.
Typically, the operator will try to get the edge of the grinding wheel down into the recesses/countersinks, entailing that the grinding wheel is destroyed and only an uneven grinding of the recess/countersink is achieved.
In U.S. Pat. No. 4,493,170 is shown a grinding wheel with a number of grinding strips. The drawback of this type is that the grinding strip does not cover the entire surface of the grinding wheel, whereby is required a great mobility of the grinding wheel in order to grind a surface.
Furthermore, uneven grinding of the surface occurs, because the shape of the grinding strip/grinding wheel does not compensate for the difference in speed from centre of the grinding wheel and outwards.
In EP 0 566 761 is shown a grinding wheel with a fraction of surfaces inclining out-wards and where lying grinding strips are fitted on this fraction. The drawback of this type is that one is required to tip/turn the grinding wheel in order to utilise the grind-ing strips optimally.
In JP 57-001669 a grinding wheel mentioned in the introduction is disclosed. This grinding wheel is provided with polishing members in slanted position and with sand paper items having an elongate outer edge corresponding to the length of the polishing member.